Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Regulation of secretory component by glucocorticoids in primary cultures of rat hepatocytes.

Abstract: The present study examined the effects of steroid hormones on the production of secretory component (SC) by rat hepatocytes in cell culture. When hepatocytes were incubated in the presence of cortisol (10(-6) M), the levels of SC in media increased significantly after 2 days of incubation. This response was dose-dependent and specific for glucocorticoids because progesterone, dihydrotestosterone, and estradiol had no effect. When estradiol was added to the incubation media along with dexamethasone, a known potent synthetic glucocorticoid, it diminished the glucocorticoid response. The addition of cycloheximide to incubation media significantly decreased the effect of dexamethasone on SC accumulation. These findings suggest that glucocorticoid regulation of hepatocyte SC most likely involves stimulation of its synthesis. In addition, our results suggest that endogenous glucocorticoids may play a role in enhancing the clearance of IgA from blood into bile in the intact animal.

Effects of Incubation Time and Temperature on In Vitro Selective Delignification of Silver Leaf Oak by Ganoderma colossum.

Abstract: The effects of incubation time and temperature on the ability of isolates of the chlamydosporic and thermophilic fungus Ganoderma colossum (Fr.) C. F. Baker to cause selective delignification of Quercus hypoleucoides A. Camus were evaluated by standard in vitro agar block tests. Chemical and scanning electron microscopy studies of decayed wood were used to determine the extent of selective delignification or simultaneous decay caused by each fungal isolate. At 35 deg C, the percent weight loss increased from 6.1% after 4 weeks to a maximum of 32.5 to 33.0% after 16 and 20 weeks of incubation. The average percent Klason lignin-chlorite holocellulose ratios (PKL/CHC) decreased from 0.35 in the control wood block to 0.22 in wood blocks incubated for 12 weeks; this indicated selective delignification. The average PKL/CHC increased for the 16- and 20-week incubation periods, indicating greater removal of polysaccharides during longer incubation periods. In temperature studies, the percent weight loss after 12 weeks was 26 to 27% between 30 and 40 deg C and less than 16% for the 25 and 45 deg C treatments. The average PKL/CHC ranged from 0.18 to 0.16 between 35 and 40 deg C, whereas they were 0.23 and 0.31 for the 25 and 45 deg C treatments, respectively. Scanning electron microscopy confirmed an optimum temperature range near 35 to 40 deg C and incubation times of 8 to 12 weeks for selective delignification. Under these conditions, ray parenchyma, fiber tracheids, and vessels were devoid of middle lamella; pit regions of cells were visible with significantly enlarged apertures; and individual cells were separated and clearly delimited. Extensive delignification of wood occurred throughout the wood blocks evaluated. Incubation times longer than 12 weeks resulted in greater degradation of wood cell walls and thus in greater removal of the polysaccharide component of the wood. For incubation times of 4 weeks or a temperature of 25 deg C, limited to no degradation of cells was observed. At 45 deg C, walls of fiber tracheids were eroded and ray parenchymal cells were extensively degraded, indicating that simultaneous degradation of cell walls occurred. Thus, the incubation temperature influenced the type of decay by G. colossum observed on oak wood blocks: extensive selective delignification at 35 to 40 deg C after more than 8 weeks of incubation or simultaneous decay at 45 deg C with 14% weight loss after 12 weeks of incubation. Isolates of G. colossum may prove useful in studies on mechanisms of delignification and biotechnological applications (e.g., biopulping) of lignin-degrading fungi.

Sex differences in optimal incubation temperatures in a scincid lizard species.

Abstract: Most theoretical models for the evolution of temperature-dependent sex determination (TSD) rely upon differential fitness of male and female offspring incubated under different thermal regimes. However, there are few convincing data on this topic. We studied incubation effects in a lizard species (Bassiana duperreyi, Scincidae) with genotypic sex determination, so that we could separate effects due to incubation temperatures from those due to offspring gender. We incubated eggs under two different fluctuating-temperature regimes that simulated hot and cold natural nest-sites. The effects of our incubation treatments on phenotypes of the hatchling lizards (morphology and locomotor performance) differed between the sexes. Females emerging from eggs exposed to the “hot nest” treatment (diel cycling, 23–31°C) were larger, and ran faster, than did their sisters from the “cold nest” treatment (16–24°C). Males showed a smaller and less consistent phenotypic response than females. These incubation-induced responses were relatively stable during the first few weeks of life post-hatching, at least in captive lizards maintained under laboratory conditions. These kinds of sex differences in the phenotypic responses of hatchling reptiles to incubation conditions provide a plausible basis for the evolution of temperature-dependent sex determination in reptiles.

Long term and standard incubations of WST-1 reagent reflect the same inhibitory trend of cell viability in rat airway smooth muscle cells.

Abstract: The WST-1 assay is an efficient test for cell viability measurement and the standard incubation time is 2h In order to test if one-time addition of WST-1 reagent can reflect the relative cell viability trend of the testing agents at different time points, the effects of 2h standard incubation time and long term incubation time (2h+24h, 2h+48h) of WST-1 were compared in the rat airway smooth muscle cells (ASM cells) after adding of the testing protein MRP-14 Our study demonstrated that the effect of different dosages of the protein after 2h WST-1 incubation on ASM cells showed a tendency of inhibition and achieved the maximal inhibition effect at 72h The relative cell viability trend of the 2h+24h group was the same to that of the 2h WST-1 incubation, which means that 24h prolonged incubation time of WST-1 reagent could still reflect the relative cell viability trend In conclusion, the study suggested that the WST-1 is a proper candidate reagent for continuous monitation of cell viability